


Swapped Bodies: Fell Route

by yupimgross



Category: Undertale (Video Game)
Genre: M/M, Soul Sex
Language: English
Status: Completed
Published: 2016-04-08
Updated: 2016-04-08
Packaged: 2018-06-01 01:35:09
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 3,319
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6495592
Author URL: https://archiveofourown.org/users/yupimgross/pseuds/yupimgross
Summary: <blockquote class="userstuff">
              <p>Undertale Papyrus has swapped bodies with Underfell Papyrus! Oh no! </p><p>But that won't get him down! He would just use this opportunity to give Underfell Sans some well-needed love and attention!</p>
            </blockquote>





	Swapped Bodies: Fell Route

**Author's Note:**

> Based off [the comic](http://ursik-l-in-junk-mind.tumblr.com/post/141680342613/fell-route-the-timeline-where-sans-is-almost-a) by [ursick-I](http://ursik-l-in-junk-mind.tumblr.com).

Bones smashed into the door, a deadly warning to the imposter that came through it.  
   
   
Just who the fuck was this guy? What the hell was he trying to do, impersonating his brother?  
   
Sweat beaded on his skull, nervous that this might be some kind of trick. Maybe this was his brother? Some elaborate scheme to try and trip him up?  
However, as he remembered the aloof, carefree, and downright moronic way he had entered into their house, crying out in his brother’s gruff voice, “NYEH HEH HEH! THE GREAT PAPYRUS IS BACK!” He really couldn’t see his bro doing something so ridiculous. He’d probably die before stooping so low.  
   
   
He eyed the dazed and confused skeleton before him. "you’re not my brother. what’s your intention, chump?” He sure looked like his brother, right down to the scar over his left eye…  
   
If he had any lingering doubts before, they were blown to smithereens as the skeleton before him beamed in delight. “THIS IS SO COOL!” He looked like he was going to bounce off the walls with glee.  
   
It was a little unnerving seeing boss act like that.  
   
“Is this how you greet your brothers in this timeline? Using bone tricks??”  
   
Jesus christ…was the guy even listening to him? Well, he guessed it didn’t matter. This guy was definitely not boss. Not only was he terrible at acting, but he was a complete dumbass. Sans could’ve killed him! Did he know nothing about the dangers of Underfell? Big fucking idiot, walking around, barging into monsters’ houses-   
   
“NYEH!” Sans’ thoughts were cut-off as not-boss wrapped him into an enormous hug.  
He stiffened in surprise and shock, having a hard time processing the strange series of events. What the hell-? The dumbass Papyrus began to speak, sounding so fucking hyped about the whole thing it was sickening.  
“To start the day of me being your temporary brother, I must give you a “sibling hug”!” He nuzzled his skull against his own, making happy little sounds as he did so.  
   
   
   
Temporary brother? _Sibling hug?_ Sans grinned to himself. He’d heard someone else use that term before…  
   
“Me and Fell Papyrus had an accident that switched our bodies! But don’t worry, The Great Papyrus can be shaped like anyone’s brother!”  
   
 Oh, so, this was his brother? Or…at least his body? Burying his face into the other’s scarf, he took in his scent. Sweat, musk, and blood. It was his brother''s scent alright... But the person inside was Undertale Papyrus, huh?   
   
His grin widened. His brother’s body…with a sweet, innocent soul inside it.  
   
Fuck yes.  
   
The arms around him pulled him tighter. “I know you two don’t get along really well…” His brother’s body sighed and spoke a bit gentler, making Sans pause. “So I’m going to spend all day with you as your brother!”  
   
He had never heard boss speak in such a way.  
   
   
   
But, then again…this wasn’t boss, now was it?  
A big, toothy smile stretched across his skull. “ya mean… _all_ day?”     
   
The not-his-Papyrus was quick to reassure him. “Of course, my new brother! The Great Papyrus is totally ready-“  
   
   
Sans let his teleportation magic engulf the two of them, the other skeleton gasping out a quick “Wowie?!!” before he warped them to his bedroom.  
   
Oh, man! Oh, man! This was gonna be priceless! Whipping out his phone, he scampered over to the dresser. He set the video recorder, and could hardly control the laugh that threatened to break form his teeth. Heh heh heh...boy, wouldn’t this be fun to show boss later?  
   
Going back to the mattress, he grinned down at the confused and dazed skeleton.  
Fuck, it was really satisfying seeing boss look like that. Even if it wasn’t really boss.  
   
The Papyrus looked up at him with complete innocence. “Wh-Where am I? Am I…on the bed?” He shifted about, trying to gain a bearing on his surroundings.  
   
   
Sans was quick to hover over him, placing a hand to his chest, and gently pressing him down on to the mattress. “heh, you see…” He soothed, holding the other’s confused gaze. “usually around this time…me and boss have some, you know, _play time_.” He gently tugged at the dark armor at his ribs. “Since boss isn’t here…you have to replace him.”  
   
   
Oh, god, he’d never been allowed to touch boss like this before.  
   
The other Papyrus looked down at his hands upon his armor with worry. “This sound fine! But… Why do you have to move your hands under my-AHH!“  
   
Sans slipped his hands beneath the armor, lavishing in the raw sound his brother’s body made as he brushed along the sensitive ribs nearest the bottom. He knew what boss liked. “well,” He purred, “this feels best, doesn’t it?”  
   
   
He groaned lightly to himself as his brother squirmed beneath his touches, his hands searching for a handhold as his breath came in unsteady, whispered pants. “Ah…Nyeh…” Sans ran his hands along his ribs, and trailed along his spine. “Not there…” His brother breathed as Sans traced each vertebrae with teasing lightness, making the body beneath him gasp and moan. “It’s weird…”  
Sans knew what his brother liked. He was just never given the chance to please him like this.  
   
God, boss would love it, apparently. The Papyrus on the bed was a shivering mess. His sockets heavy, he gasped as Sans ran his hands away from his ribs. He brushed across his pelvis, a sharp cry and a whimper made Sans' soul burn in his chest. He'd get back to that spot later...  
   
   
Coming to a rest at his thighs, he grabbed a fistful of his bone-tight pants and tore them with his claws. He always wondered why Papyrus wore such a skimpy outfit. It was like he wanted to tease him. As the cloth tore away, he felt a wave of satisfaction at Papyrus’ surprised expression.  
   
God, this had to be the best day of his fucking life. “you’re pretty sensitive here, aren’t you?” He breathed against the newly exposed femur. The other shivered in his grasp, not sure how to wrap his skull around all that was happening. Watching his brother’s face, he ran his hot tongue against his inner thigh.  
   
The other cried out, “NO! AHHH!!” His sockets clenching closed against the feeling.  
Oh, god...

Sans moaned against his thigh as the skeleton's brows pinched in both worry and pleasure. His ribs rising and falling with shaky breaths. Lovely, quiet sounds breaking from his teeth.  
   
Sans grinned as he continued to run his tongue up and down the bone. The other whimpered and shivered, his hands clenching around the sheets on his bed, desperate in their search for support. Deep, groaning mewls broke from him as Sans continued to tease and touch.  
   
God, the sounds he made were delicious. He hoped his phone would be able to pick them up.  
   
   
The soul in his chest burned with desire for his brother. It always had. He wanted to do these things with boss...but he'd never been allowed. He was always the one to be pleasured, to be the bottom, to receive and never allowed to give.   
   
Sockets heavy, the other Papyrus tried to sit up.   
Sans knew this was wrong. He knew this wasn't really his brother. He knew he was taking advantage of the naive skeleton.  
   
But he just wanted to do these things so badly to boss.  
He just wanted to see him wracked with pleasure, from him and him alone.  
   
   
Seeing the fear begin to settle in Papyrus' eyes, Sans laid a hand upon his spine again. "aw, don't be scared." Gently, he moved his hand along its length, causing the other to sigh.  
"doesn't that feel good?" He ventured.  
   
Papyrus, uncertain and confused, replied honestly. "Y-yes..."  
   
Sans smiled at him, loving the blush that slowly crept over his brother's sharp cheekbones. Papyrus turned his head away, as if afraid to look at him.   
The smaller skeleton gripped him beneath his chin and brought the other to look at him. Shit, those lovely red eyes...filled with uneasy desire...for _him_.   
"don't ya want more?" He picked up his pace, making certain his phalanges dipped to lightly scrape at the discs.  
   
   
Trying to hold back a moan, the other clenched his teeth. He watched Sans with fear, excitement, and confusion. Huffing as Sans gripped his spine tighter, he choked out a response, "I-I don't know..."  
   
But Sans knew.  
He knew he wanted this.  
   
Though...he did feel kinda bad about doing this to the rather…soft, Papyrus.  
   
   
Oh, but to see his brother's body beneath him, shaking and panting, sockets heavy and glistening with un-shed tears, his body so willing and ready...  
   
Sans just wanted to take control of his brother's body more.  
   
Sorry, Undertale Pap.  
   
   
   
Sans rolled up his armor and leaned forward to lick along his ribs.  
   
"NYEH-AH!" Papyrus cried out at the sudden hot wetness of his tongue, a hand flying forward to grip at his hoodie.   
   
His spine arched in his hands, and Sans settled into a nice, languid jerk, squeezing as he did so.  Thrown off from the spike in pleasure, Papyrus fell back onto the mattress. Ribcage rising and falling in heated pants and moans, his orange soul shone brightly beneath his armor.  
   
Loosing a moan of his own, Sans crawled forward to straddle his hips.  
   
His brother's red eyes stared up at him, glazed from the wonderful sensations Sans was inflicting upon him.   
Sans ran his fingers Along his body, admiring the curves and edges. He trailed his way to his face, gripping his marred skull between his hands.  
The other moaned as he licked along his scar, then to his jaw, and clanked his way down to his throat. Sharp claws dug into his back, and he answered with a nip in kind to his collar.  
Papyrus gasped from the tease, his soul beating so loudly Sans could hear it. Hell, he thought he could actually feel it's beat.  
   
Grinning, he pulled away to look down at his brother.   
   
Fuck, he was...  
He was...  
   
"What?..." Papyrus breathed, tears streaming from his sockets, his hands gripping onto Sans' shirt for dear life, those red eyes trained on him with such wonderful desperation and foggy desire.  
   
He was beautiful.  
   
   
Sans moaned and began to grind his pelvis against the other's.  
"AH! S-SANS!" Papyrus screamed at the sensation, gritting his teeth, and trying to meet his hips with his own.  
   
"heh, yeah...just keep saying my name, bro." He grinned as he ran his hands back along his ribs, this time he was rough, he was fast, just like boss liked it.  
   
Papyrus was an absolute wreck, his soul burning within, so bright Sans couldn't help but smile. God, he was really fucking him up. His own soul was pretty bright, but damn, look at this guy!   
"Sans? I-I can't... I think...uhn. Please...I n-need..." His brother's body was twined about him, shifting and rubbing, unable to get what it desired. Papyrus didn't know what it desired.  
   
   
Luckily, Sans did.  
   
   
Feeling that he'd teased and tortured him enough, Sans ran his fingers up his spine, up into his ribcage...  
   
And gently took hold of Papyrus' soul.

He brought it out from his body, watching the other's expression. His socket's widened at seeing his soul in Sans' hands, fear and nervousness making his own soul beat hard. Running his thumb along the outer edge, he whispered, "it's ok, Pap. i won't hurt ya." The tender rubbing made the other lie back with a sigh, his eyes closing against the feeling.   
   
"Sans..." He moaned, his hands moving to grip at the sheets beneath him.   
   
Sans smiled down at the soul in his hands. It wasn't his brother's. It was a good, kind soul. Warmth radiated from it and a gentleness, no, a subtle softness to it made him sigh. He suddenly  felt really terrible for doing this to Papyrus.  
It might be his brother's body, but this was Papyrus' soul.  
   
   
He would have to treat him right. It was only fair.  
   
Bringing the tender soul to his teeth, he clanked a kiss to it.  
He grinned at the other's accompanying loud groan, never having felt anything so wonderful. Sans let his broad tongue loll from his teeth, and licked along the edge.  
The body beneath him jolted, a scream tearing from him as he bucked.  
Warm magic oozed from the heart in his hands, its owner already so aroused it was practically dripping onto his palms. He hungrily lapped at the orange magic, finding that it was musky and slightly sweet. Eyes trained on his brother's body, he sucked it into his mouth, wrapping his tongue about it and licking it clean.  
   
"NYEH! SANS! AH, S-SANS!"   
He was close. His hips grated against his own, tears streaming from his sockets as his eyes rolled back into his head. Heated breaths and hot moans the only sounds he seemed capable of making as his words devolved into incomprehensible nonsense.  
 

A cruel grin broke across Sans' skull.  
   
While he loved pleasuring the imposter in his brother's body, Sans had yet to get anything out of this exchange.  
Oh, he'd treat Papyrus right...but on his own terms, of course.  
   
   
He let the soul slip from his mouth, and held it in his hands, letting it gush and beat. Letting it cool off a bit, bring it back from the edge a bit. He wasn’t about to let him cum just yet.  
   
Dazed and dizzy, Papyrus focused back onto him. “W-why…why did you s-stop?”  
Sans chuckled at the angry expression forming on the other’s face. He almost acted like the real boss! Almost. “heh, calm down, bro.” Releasing the other’s soul, it retracted back beneath his ribs, bobbing in excitement. Sans shrugged off his hoodie, and Papyrus watched him with curious eyes. To Sans’ surprise, the other trailed his hands from the mattress up to rest on his thighs. Looks like Pap was getting a bit more comfortable with “play time”.

Well, he’d try to not be a sour-sport.

Shimmying out of his sweater he tossed it aside.

   
“Wowie.” Papyrus breathed as he took in the smoldering, red soul glowing within Sans’ ribcage. It beat fiercely at the attentive stare, and Sans smiled.  
“You like that?” He meant to be a shithead about it, but Papyrus was so goddamn naïve, innocent, and honest it was painful.  
“Yes.” He sighed, and to Sans’ surprise, he raised his hands up and placed them on his ribs. The inexperienced motions prodded and explored along his bones, wanting to please.  
   
   
Surprised by the other Papyrus’ actions, he choked back a moan at his brother’s body touching him in such a way, so full of interest and arousal over his soul. The look of intrigue in his red eyes… The look of his brother actually _wanting_ to touch him… Oh, god. It was too much. His soul felt fit to burst already.

Sans needed to snap the fuck out of it.

   
He growled and grabbed the other’s wrists.  
Papyrus gasped at his sudden roughness, and he smiled down at him, using his other hand to shove his armor up. Before the other skeleton knew what was happening, he crushed their ribs together, and clanked their teeth in a hasty kiss.

His brother’s eyes fluttered closed, a groan on his tongue as Sans rubbed their bodies together, grinding their ribs. As his brother’s sharp teeth parted, he wasted no time shoving his tongue into his mouth. He attacked him without mercy. He loved the way he tasted, and the fact that he was suddenly so inexperienced, so willing, so virgin…god, it made him taste all the better.

Hands wrapped about his skull, and the other’s tongue answered his own, sloppy and uncertain, but full of vigor.  
   
   
They moaned and panted as they warred, their limbs tangling and bones rustling against one another.  
   
   
His soul latched onto the other’s, so aroused it was pulsing desperately in its need to share its magic. Reaching within Papyrus’ chest cavity, he pulled out the bright orange soul. Sans gasped as a hand wrapped about his own.  
“c-careful!” His eyes widened in slight anxiety, uncertain if he could trust this monster with it. It was a bit...fragile. He hated the fact, but it was true. Papyrus could crush him to dust if he so wanted.

Papyrus' voice quiet and sweet, he soothed the small skeleton's worries. "O-ok…I will be, Sans.” He gently brought out the weak soul from his ribs, so much dimmer than the small heart-shaped sun in his own palm. Yet, Papyrus looked at it like it was something wonderful. Following Sans’ example, he clanked a kiss to it, drawing out a moan from the smaller skeleton.  
   
Oh, god.  
Seeing boss’ body doing that to him, kissing his soul with such a tender, glazed, and pleasured expression…  
His soul squelched out a few beads of red liquid, dripping down Papyrus’ arm. The other looked at it curiously, and, before Sans could say anything, licked the magic from his bones.  
   
F-FUCK! That was hot as shit! Holy hell?! Goddamnit, boss’ body was fucking hot as hell, and the fact that this was _Undertale Papyrus_ acting like this made it sexier by like a fucking million percent. Good lord, maybe he’d have to send this video to Undertale Sans…  
He grinned at the thought.  
   
He’d give ‘em both a _real_ good show.  
Right after he gave Pap a good time.  
   
   
Leaning back in, he crushed their chests together, and kissed him again. Their souls snapped together like two magnets, their magic wrapping about one another. Papyrus screamed, and Sans ravaged his mouth, moaning and groaning as their soul mingled and twined.  
   
Shots of blazing heat radiated to his core, burning through his bones. Papyrus intense personality flaring up inside him. God, he felt good!  
"ahh...sh-shit..." He growled against his cheek. Their souls beat in asynchronous rhythms, the harsh feeling sending waves of magic crashing through their bones.  
Papyrus panted against him as Sans rubbed their bodies together, setting a pace, setting a rhythm.

  
"Sans! Oh my god...Sans..."  
Oh fuck, hearing boss call his name, so close...  
Huffing, he wrapped his arms around Papyrus' chest, pulling them closer. Their souls were pressed closer, melding and forcing their individual beats to mesh.  
They strained against one another, red and orange. The slickness from them coated their bones, driving them faster as they settled into a beat of their own.  
"hah, ah...Pap...i..." Sans panted, the skeleton below him a muddled mess. He chanted and screamed his name, his hands grasping him for all he was worth.

 

They gasped as their souls aligned, their magic becoming one for the briefest of moments. Bright light burst from their chests, magic sparking in the air and crackling along their bones.

Lying together in a heap on his mattress, they caught their breath. Warmth spread through his bones and he groaned gently. For a few moments they were one, their souls mingling before separating back to their separate bodies.

  
"Wowie..." Papyrus breathed, his skull lifting from the mattress to grin at Sans. "That was incredible, Sans!"

Sans blushed. A compliment was a compliment after all, and not something he was used to receiving. "yeah...thanks..." He felt a twinge of anger, wishing his brother would say such things to him. Why the fuck was it so hard for him to be a bit supportive every now and then?

  
He grinned evilly as he remembered the phone still taping the whole scene in his dresser. Heh, well, he supposed his bro _did_ say such things to him.  
Sans had even got it all on camera.

"you're a pretty awesome bro, for the _record_. heh heh!" Giving a toothy smile, he winked at the camera.

 

 

**Author's Note:**

> I loved this comic. Can't you tell?


End file.
